S=1/2 Heisenberg Chain with Bond Alternation in the S^z^-S^z^ Coupling

The effect of bond alternation in the S z - S z coupling ( z -alternation) on the dimerization in an S =1/2 Heisenberg chain is investigated both analytically and numerically. The spin Hamiltonian is transformed into the phase Hamiltonian, and the variational method is used. An analytical study shows that the z -alternation plays an important role and brings about the dimerization when there is no bond alternation in the S x - S x and S y - S y couplings. The results of numerical diagonalization for finite systems support the above analytical conclusion.The effect of bond alternation in the S z - S z coupling ( z -alternation) on the dimerization in an S =1/2 Heisenberg chain is investigated both analytically and numerically. The spin Hamiltonian is transformed into the phase Hamiltonian, and the variational method is used. An analytical study shows that the z -alternation plays an important role and brings about the dimerization when there is no bond alternation in the S x - S x and S y - S y couplings. The results of numerical diagonalization for finite systems support the above analytical conclusion.

Journal of the Physical Society of JapanOct 15, 19924 citations

The S=3/2 Heisenberg chain in a magnetic field

Gábor Fáth, Paolo Maria Santini, Zbigniew Domański +1 more

APSMar 1, 19970 citations

Multimagnon excitations in alternating spin/bond chains

B. W. Southern, J. L. Martínez Cuéllar, David A. Lavis

The nature of multimagnon excitations in alternating spin/bond ferromagnetic chains are studied using a combination of scaling methods and the recursion method. Two-magnon excitations for a Heisenberg chain with either alternating spin magnitudes, $S$ and ${S}^{\ensuremath{'}},$ or alternating nearest-neighbor couplings, ${J}_{1}$ and ${J}_{2}$ can be studied using real-space rescaling techniques. These results are then used to investigate three-magnon excitations using the recursion method.The nature of multimagnon excitations in alternating spin/bond ferromagnetic chains are studied using a combination of scaling methods and the recursion method. Two-magnon excitations for a Heisenberg chain with either alternating spin magnitudes, $S$ and ${S}^{\ensuremath{'}},$ or alternating nearest-neighbor couplings, ${J}_{1}$ and ${J}_{2}$ can be studied using real-space rescaling techniques. These results are then used to investigate three-magnon excitations using the recursion method.

Physical review. B, Condensed matterOct 1, 19986 citations

S

and ${S}^{\ensuremath{'}},$ or alternating nearest-neighbor couplings,

{J}_{1}

and

{J}_{2}

can be studied using real-space rescaling techniques. These results are then used to investigate three-magnon excitations using the recursion method.